Replaces @length memory blocks in @buffer starting at @idx with @mem.
If @length is -1, all memory starting from @idx will be removed and replaced with @mem.
@buffer should be writable.
an index
a length should not be 0
a #GstMemory
See Implementation
Replaces @length memory blocks in @buffer starting at @idx with @mem.
If @length is -1, all memory starting from @idx will be removed and replaced with @mem.
@buffer should be writable.